tcg/loongarch64: Implement tcg_out_mov and tcg_out_movi

Signed-off-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211221054105.178795-10-git@xen0n.name>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
WANG Xuerui 2021-12-21 13:40:43 +08:00 committed by Richard Henderson
parent fae2361dc9
commit dacc51720d
1 changed files with 137 additions and 0 deletions

View File

@ -247,6 +247,141 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
tcg_out_opc_dbar(s, 0);
}
static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
{
if (ret == arg) {
return true;
}
switch (type) {
case TCG_TYPE_I32:
case TCG_TYPE_I64:
/*
* Conventional register-register move used in LoongArch is
* `or dst, src, zero`.
*/
tcg_out_opc_or(s, ret, arg, TCG_REG_ZERO);
break;
default:
g_assert_not_reached();
}
return true;
}
static bool imm_part_needs_loading(bool high_bits_are_ones,
tcg_target_long part)
{
if (high_bits_are_ones) {
return part != -1;
} else {
return part != 0;
}
}
/* Loads a 32-bit immediate into rd, sign-extended. */
static void tcg_out_movi_i32(TCGContext *s, TCGReg rd, int32_t val)
{
tcg_target_long lo = sextreg(val, 0, 12);
tcg_target_long hi12 = sextreg(val, 12, 20);
/* Single-instruction cases. */
if (lo == val) {
/* val fits in simm12: addi.w rd, zero, val */
tcg_out_opc_addi_w(s, rd, TCG_REG_ZERO, val);
return;
}
if (0x800 <= val && val <= 0xfff) {
/* val fits in uimm12: ori rd, zero, val */
tcg_out_opc_ori(s, rd, TCG_REG_ZERO, val);
return;
}
/* High bits must be set; load with lu12i.w + optional ori. */
tcg_out_opc_lu12i_w(s, rd, hi12);
if (lo != 0) {
tcg_out_opc_ori(s, rd, rd, lo & 0xfff);
}
}
static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd,
tcg_target_long val)
{
/*
* LoongArch conventionally loads 64-bit immediates in at most 4 steps,
* with dedicated instructions for filling the respective bitfields
* below:
*
* 6 5 4 3
* 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
* +-----------------------+---------------------------------------+...
* | hi52 | hi32 |
* +-----------------------+---------------------------------------+...
* 3 2 1
* 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
* ...+-------------------------------------+-------------------------+
* | hi12 | lo |
* ...+-------------------------------------+-------------------------+
*
* Check if val belong to one of the several fast cases, before falling
* back to the slow path.
*/
intptr_t pc_offset;
tcg_target_long val_lo, val_hi, pc_hi, offset_hi;
tcg_target_long hi32, hi52;
bool rd_high_bits_are_ones;
/* Value fits in signed i32. */
if (type == TCG_TYPE_I32 || val == (int32_t)val) {
tcg_out_movi_i32(s, rd, val);
return;
}
/* PC-relative cases. */
pc_offset = tcg_pcrel_diff(s, (void *)val);
if (pc_offset == sextreg(pc_offset, 0, 22) && (pc_offset & 3) == 0) {
/* Single pcaddu2i. */
tcg_out_opc_pcaddu2i(s, rd, pc_offset >> 2);
return;
}
if (pc_offset == (int32_t)pc_offset) {
/* Offset within 32 bits; load with pcalau12i + ori. */
val_lo = sextreg(val, 0, 12);
val_hi = val >> 12;
pc_hi = (val - pc_offset) >> 12;
offset_hi = val_hi - pc_hi;
tcg_debug_assert(offset_hi == sextreg(offset_hi, 0, 20));
tcg_out_opc_pcalau12i(s, rd, offset_hi);
if (val_lo != 0) {
tcg_out_opc_ori(s, rd, rd, val_lo & 0xfff);
}
return;
}
hi32 = sextreg(val, 32, 20);
hi52 = sextreg(val, 52, 12);
/* Single cu52i.d case. */
if (ctz64(val) >= 52) {
tcg_out_opc_cu52i_d(s, rd, TCG_REG_ZERO, hi52);
return;
}
/* Slow path. Initialize the low 32 bits, then concat high bits. */
tcg_out_movi_i32(s, rd, val);
rd_high_bits_are_ones = (int32_t)val < 0;
if (imm_part_needs_loading(rd_high_bits_are_ones, hi32)) {
tcg_out_opc_cu32i_d(s, rd, hi32);
rd_high_bits_are_ones = hi32 < 0;
}
if (imm_part_needs_loading(rd_high_bits_are_ones, hi52)) {
tcg_out_opc_cu52i_d(s, rd, rd, hi52);
}
}
/*
* Entry-points
*/
@ -262,6 +397,8 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
tcg_out_mb(s, a0);
break;
case INDEX_op_mov_i32: /* Always emitted via tcg_out_mov. */
case INDEX_op_mov_i64:
default:
g_assert_not_reached();
}